A trim board on which an ornament member (an interior member) is mounted has been known as an example of an interior component of a vehicle. The ornament member includes a panel and hollow mounting projections. The panel has a longitudinal shape that extends in the horizontal direction. The mounting projections protrude from a back surface of the panel toward the trim board. The hollows of the mounting projections are screw holes in which screws are fitted. An outer perimeter of each mounting projection is substantially the same as a perimeter of each through hole. Distal portions of the mounting projections are fitted in through holes of the trim board at a substantially right angle and the screws are fitted in the respective screw holes of the mounting projections. With the mounting projection, the through holes, and the screws, the ornament member is fixed to the trim board, specifically, to a surface of the trim board on a vehicular compartment side. Each mounting projection includes a rib at a projection base thereof closer to the back surface of the panel. The rib continues to the back surface of the ornament member.
In a collision, the vehicle may collide against an object such as a pole that extends in an upper-lower direction of the vehicle. In such a case, a portion of the vehicle body which has hit the pole may be dented. Namely, a portion of the interior component corresponding to the portion of the vehicle body may be pushed by the portion of the vehicle body toward the interior side of the vehicle and deformed. The trim board may be curved and the ornament member mounted to the trim board may be curved along the ornament member. If the trim board and the ornament member are curved, a force may be applied to the projection base of each mounting projection in a direction to displace the mounting projection from the corresponding through hole toward a portion of the ornament member to which the load is applied. However, the distal portions of the mounting projections may not be displaced from the respective through holes because the distal portions of the mounting projections are fixed. Therefore, stresses may be applied to the projection bases of the mounting projections. With the stresses, the angle of the distal portion of each mounting projection relative to the corresponding through hole may change from the original angle, that is, from the right angle. If the stresses are larger than a tolerance, the mounting projections may be broken at the projection bases or the ornament member may be broken.
One of solutions for reducing the breakage of the mounting projections is to increase rigidity of the mounting projections or to increase the number of ribs that continue from each mounting projection to the back surface of the ornament board. Another solution is to increase the thickness of the ribs. However, ribs having such configurations may create a dent in a decorative surface of the ornament member (i.e. a surface of the ornament member opposite to the back surface). Another solution to reduce the breakage of the mounting projections is to use materials having higher rigidity for the ornament member. However, such a material-based solution limits the materials applicable to the ornament member to some materials having high rigidity and such materials may limit the design range of the ornament member.